A series of boron-modified low-gold-content Au-based catalysts were prepared by impregnation. Characterization by N2 adsorption/desorption, XPS, H2–TPR, HCl/C2H2–TPD, TG, TEM, and SEM was applied to analyze the catalyst. Compared with the unmodified catalyst, B-modified Au0.25%/BAC-20% exhibited better performance (acetylene conversion increase by 21.4% and selectivity to VCM of more than 99.5%) at a space velocity of 770h−1 and 150°C. The results indicated that the presence of boron species is favorable to the stabilization of catalytically active Au3+ species and the inhibition of Au3+ to Au0 during acetylene hydrochlorination, and hence improves the catalytic stability. In addition, the presence of boron species can effectively inhibit carbon deposition and also inhibit the catalyst sintering during the reaction. TPD experiments revealed that not the adsorption ability of C2H2 but the adsorption ability of the HCl played a crucial role in boron-modified Au-based catalysts.